The present disclosure relates to the technical field of energy storage devices, and in particular, to a secondary battery. The secondary battery includes a case, an electrode assembly, and a top cover assembly. The case has an opening, and the electrode assembly is received in the case. The top cover assembly includes a top cover plate and an electrode terminal disposed on the top cover plate. The top cover plate is disposed at the opening. The connection sheet is connected between the electrode assembly and the electrode terminal. The secondary battery provided by the present disclosure further includes an insulation thermal-dissipation member disposed between the top cover plate and the connection sheet. The insulation thermal-dissipation member has a thermal conductivity larger than 1 W/(m·k).